Chapter 29 Lecture Enrichment Ideas
The size difference between viruses and bacteria, and between average bacteria and eukaryotic cells can be illustrated: If an eukaryotic cell were the size of a large lecture room, a bacterium would approximate the size of a chair or desk, and a virus would be smaller than a pencil.
Diagrams of the entry, replication, and release of DNA and RNA viruses in host cells are best illustrated by drawing the sequences and providing line diagrams. Viruses are almost always illustrated in black and white—the electron microscopy world. Colors in such illustrations are artificial enhancements.
Discuss the possible origins of viruses, with emphasis on the fact that bacterial, plant, and animal viruses have genes that are more like the genes of their host cells than like other kinds of viruses. One possibility is that the viruses represent parts of the host cell genome that became semi-independent. Ask if this would work for RNA viruses.
Examine the products that a provirus (integrated virus) makes that cause human diseases when the human is infected by a lysogenic bacterium, such as diphtheria toxin or the factor in Streptococcus that produces scarlet fever or rheumatic fever.
Discuss the reproductive pathway for the AIDS virus, pointing out the areas in its replication that might be attacked by antiviral drugs.
Biographical readings from books such as The Virus Hunters or The Microbe Hunters provide the context for early work by Koch and Pasteur. Such reading excerpts reveal a very human set of researchers who knew their work meant life or death for thousands.
Describe why the production of endospores is important in the survival of some forms of bacteria.
Ask where a student could point out a sterile location in a house; the oven is probably the closest to sterile.
What can we do to maintain a sterile field in an operating room where not all objects can be boiled?
Back to Lecture Enrichment Ideas